Week 1: Atomic Orbitals and Electronic Structure

What do Quantum numbers tell us about atomic orbitals?

The energy, size, shape and orientation of the orbitals

What is the symbol for the principle quantum number?

n

What values are allowed for n?

Integer values. eg, 1,2,3…

What does the quantum number n describe?

The energy and size of an atomic orbital

What is the symbol for the angular momentum Quantum number?

l

What is the symbol for the magnetic quantum number?

m_l

What is the symbol for the spin quantum number?

m_s

What are orbitals of the same n but different l values?

sub-shells

What are the allowed value of l?

0 to (n-1)

What do the values of l determine?

The name of the orbital

what type of sub-shell is L=0

s

what type of sub-shell is L=1

p

what type of sub-shell is L=2

d

what type of sub-shell is L=3

f

What are the allowed values of m_l?

from -l to +l

What does the quantum number m_l tell us about an orbital?

Its orientation in space

What are the allowed values of m_s?

-1/2 and +1/2

What is the phase of the surface boundary of an s orbital?

constant

How many nodal planes does an s orbital have?

0

How many nodal planes does an p orbital have?

1

How many nodal planes does an d orbital have?

2

What is the shape of an s orbital?

spherical

What is the shape of a p orbital?

bi-lobed

What is a nodal plane?

The place where the electron probability is 0. there is a change in the surface boundary phase at the node.

What are the different orientations/degenerate orbitals in p called?

p_z, p_y, p_x

What are the different orientations/degenerate orbitals in d called?

d_xy, d_yz, d_xz, d_z², d_x²-y²

What happens to energy levels (E_n) as n increases?

Energy levels get closer together

Which quantum numbers does orbital energy depend on?

n and l but for hydrogen only n

why does l influence orbital energy?

Because of electron shielding

Describe the Aufbau principle.

Orbitals are filled in order of increasing energy with the lowest energy orbitals being filled first. (Building-up principle)

Describe Hund’s rule.

Electrons occupy all of the orbitals of a given sub-shell singly before pairing begins. The unpaired electrons have parallel spins.

Describe the Pauli Exclusion principle

No two electrons in an atom can have identical sets of four quantum numbers.

What is electronegativity?

The ability of an atom to attract an electron to itself